Use of the community viral load as a population-based biomarker of HIV burden.

Objectives: Recent data suggest that community viral load (CVL) can be used as a population-level biomarker for HIV transmission and its reduction may be associated with a decrease in HIV incidence. Given the magnitude of the HIV epidemic in Washington, District of Columbia, we sought to measure the District of Columbia's CVL.

Design: An ecological analysis was conducted.

Methods: Mean and total CVL were calculated using the most recent viral load for prevalent HIV/AIDS cases reported to District of Columbia HIV/AIDS surveillance through 2008. Univariate and multivariable analyses were conducted to assess differences in CVL availability, mean CVL, proportion of undetectable viral loads, and 5-year trends in mean CVL and new HIV/AIDS diagnoses. Geospatial analysis was used to map mean CVL and selected indicators of socioeconomic status by geopolitical designation.

Results: Among 15,467 HIV/AIDS cases alive from 2004 to 2008, 48.2% had at least one viral load reported. Viral load data completeness increased significantly over the 5 years (P < 0.001). Mean CVL significantly decreased over time (P < 0.0001). At the end of 2008, the mean CVL was 33,847 copies/ml; 57.4% of cases had undetectable viral loads. Overlaps in the geographic distribution of CVL by census tract were observed with the highest means observed in areas with high poverty rates and low high school diploma rates.

Conclusion: Mean and total CVL provide markers of access to care and treatment, are indicators of the population's viral burden, and are useful in assessing trends in local HIV/AIDS epidemics. Measurement of CVL is a novel tool for assessing the potential impact of population-level HIV prevention and treatment interventions.